1. Field of the Invention
The present invention relates to an optical fiber holder, an optical fiber adaptor, and an optical fiber processing device having a positioning mechanism. In particular, the invention relates to an optical fiber holder having a positioning mechanism for holding an optical fiber or an optical fiber ribbon and easily and precisely setting in an optical fiber adaptor in an optical fiber processing device while holding the optical fiber therein. The invention further relates to an optical fiber adaptor having a positioning mechanism holding the optical fiber holder in the optical fiber processing device, and to an optical fiber processing device having a positioning mechanism.
2. Description of the Related Art
In general, an optical fiber holder is mounted onto an optical fiber processing device in following various processes: the tip end of an optical fiber is cleaved and polished; the tip end of an optical fiber is optically coupled to a light source or a power meter; and the tip ends of optical fibers are fused and spliced to each other.
Such an optical fiber holder holds the tip portion and a portion close to the tip portion of an optical fiber or an optical fiber ribbon made up of a plurality of optical fibers (hereinafter, referred to as “an optical fiber” in some cases). The entire optical fiber holder is positioned and then fixed at a predetermined position on the mounting surface of an optical fiber processing device, and various processes for the optical fiber.
As conventional positioning mechanisms in optical fiber holders for use in conventional optical fiber processing devices, the following techniques (1), (2), and (3) are well known, in addition to the positioning mechanism where the optical fiber holder is directly mounted and fixed onto an optical fiber processing device at a predetermined position:                (1) Japanese patent laid-open publication number JP-A-H6-148454;        (2) Japanese patent laid-open publication number JP-A-2001-108841; and        (3) Japanese patent laid-open publication number JP-A-H11-142677.        
In the positioning mechanisms disclosed in techniques (1) and (2) the optical fiber holder is detachably mounted at a predetermined position in the optical fiber processing device through a force caused by a magnet.
Further, in the positioning mechanism disclosed in the technique (3) the optical fiber holder is detachably held and fixed by a fixing means mounted at a predetermined position in the optical fiber processing device.
However, as further explained below, problems (a), (b), and (c) exist when conventional optical fiber holders are mounted on conventional optical fiber processing devices, for example, in an optical fiber fusion splicer using the conventional optical fiber holder.
(a) There is a possibility that the following cases will make flaws (or scratches) on a surface or on a cleaved plane of the optical fiber: The side face of the optical fiber clashes or is impacted carelessly to component parts such as V-groove edges, an optical fiber clamp mechanism, a lens for observing the optical fiber, mechanism parts accompanied with this lens, and arc discharging electrode rods for use in a fusion splicing process. Because there is no guiding mechanism in the conventional optical fiber processing device for guiding the optical fiber holder, the optical fiber holder is shifted forward and backward when this holder is mounted on the mounting surface of the optical fiber processing device while clamping the optical fiber. As a result, there is a problem in which the flaw occurs in the optical fiber and the flaw causes to decrease a tensile strength of an optical fiber cable and to thereby increase a splice loss between the optical fibers.
(b) In the process in which an optical fiber is mounted in a V-groove formed in a fusion splicer and shifted to a desired position on the V-groove in order to splice the optical fibers together, there is a problem in which fine dusts are attached to the tip of or the cleaved surface of the optical fiber. Thereby, the splice loss between the optical fibers becomes high.
(c) When the optical fiber holder is mounted on the optical fiber processing device, it is necessary for an expert (skilled) operator to handle the optical fiber holder in order to set it onto the optical fiber processing device so that any part of the optical fiber projected from the tip portion of the optical fiber holder is not touched to various mechanical components around the mounting surface of the optical fiber processing device.
By the way, there are many kinds of available terminal processing devices as optical fiber preparation tools, for example, a jacket stripper, an ultrasonic cleaner, a cleaver, a fusion splicer, and the like (hereinafter, referred to as “optical fiber processing devices”). The jacket stripper strips a coating material from an optical fiber. The ultrasonic cleaner performs the cleaning of a bare fiber after the coating material is stripped from the optical fiber. The cleaver cleaves the end portion of the optical fiber. The fusion splicer fuses the optical fibers and then splices the end surfaces of both the optical fibers.
When an optical fiber is mounted on an optical fiber processing device, or when the end portion of the optical fiber is set to a measuring device such as a power meter, the optical fiber is firstly set in an optical fiber holder, and the optical fiber holder is then mounted in the optical fiber processing device.
FIG. 23 is a front view showing a configuration of a conventional optical fiber holder for holding the end portion of an optical fiber.
The conventional optical fiber holder 60 comprises a hinge pin 61, upper and lower clamping portions 62U and 62L capable of opening and closing through the hinge pin 61, and elastic materials 63U and 63L like a rubber plate corresponding to opposed surfaces of the clamping portions 62U and 62L. Between the elastic materials 63U and 63L, the optical fiber 64 is clamped. A clamping force of an approximate constant value to clamp the optical fiber 64 is given by a magnet (not shown) or a spring (also not shown).
In the holding state where the conventional optical fiber holder 60 having the above configuration holds the end portion of the optical fiber 64, when the optical fiber is set in the optical fiber cleaver in order to cleave the optical fiber in a predetermined lead length (the length of a bare fiber where the coating material has been detached), an operator sets the optical fiber in the optical fiber cleaver while positioning the end portion of the optical fiber at a graduation marked on the optical fiber cleaver. In this case, because the size of the optical fiber is so fine that it is necessary for a skilled operator to handle this positioning operation.
Further, when optical fibers are set in an optical fiber fusion splicer for performing a fusion splicing process, a coating material portion in each optical fiber is mounted on a V-groove for positioning in a fusion splicing portion in the device. This operation causes that the ends of the optical fibers are not reached to a discharging area in the fusion splicing portion by an inclination of the optical fibers or by the error of the positioning. Furthermore, there are various problems that flaws (or scratches) occurs on an end surface or a surrounding surface of the optical fiber by clashing the end surface and surrounding surface of the optical fiber with component parts such as V-groove edges and the like, and that fine dusts are attached to the end surface of the optical fiber by sliding the optical fiber on the V-groove.
FIG. 24 is a diagram showing a conventional optical fiber holder having another configuration.
An optical fiber holder 70 shown in FIG. 24 comprises a base plate 72 having a V-groove 71 for fixing the optical fiber 64 and a clamp 74 capable of opening and closing through the hinge pin 73. The optical fiber holder 70 further comprises an elastic material 75 formed on the clamping surface of the clamp 74 and a concave-shaped groove 76 formed under the base plate 72 that is detachably engaged with a positioning convex portion 81 formed on a mounting base 80 (see FIG. 25A and FIG. 25B) in the optical fiber processing device.
In the conventional optical fiber holder 70 having the configuration described above it is necessary to mount a strong magnet in the optical fiber holder 70 or in the mounting base 80 in order to fix the optical fiber holder 70 onto the mounting base 80. Or, as shown in FIG. 25A and FIG. 25B, it is necessary to equip a fixing mechanism 82 of a kind of a toggle link mechanism with the mounting base 80. Therefore the conventional optical fiber holder has a problem that the working efficiency to mount the optical fiber holder 70 on the mounting base 80 and to release it from the mounting base 80 becomes low.
Moreover, when the concave portion 76 formed in the base plate 72 is engaged with the positioning convex portion 81 on the mounting base 80, although it is possible to perform the positioning in the direction perpendicular to the longitudinal direction of the optical fiber holder 70, it is difficult to perform the precision positioning in the longitudinal direction of the optical fiber holder 70.
For example, an error operation occurs because the tip portions of optical fibers to be spliced together is not reached within the arc-discharge area when the optical fiber holder is set in the fusion splicer.
Further, for example, in order to avoid any occurrence of drop of an optical fiber from the optical fiber cleaner it is necessary to equip a fixing mechanism such as a magnet and the like for fixing the optical fiber when the tip portion of the optical fiber is cleaned while the tip portion of the optical fiber is fixed in vertical direction.
Moreover, there are many types of conventional adaptors, as shown in FIG. 26A and FIG. 26B, and FIG. 27A and FIG. 27B, for use in various measurement devices such as a power meter and the like. FIG. 26A and FIG. 26B show the adaptor 90 in which the optical fiber 64 is inserted in a small hole therein. The adaptor 100 shown in FIG. 27A and FIG. 27B has two divided portions in which the optical fiber 64 is held between them.
The adaptor 90 (see FIG. 26A and FIG. 26B) of the optical fiber insertion type has a drawback in which fine dusts are attached to the tip surface of the optical fiber 64 by contacting the tip surface of the optical fiber 64 to surrounding portions when the optical fiber 64 is inserted into a fine hole.
The adaptor 100 (see FIG. 27A and FIG. 27B) of the division type in which the optical fiber is held between the two divided-body portions has the drawback where in some cases the optical fiber is broken when the optical fiber is not set precisely in a predetermined portion.